Question

What do all electrolytes have in common?

Answer 1

They have lost/gained electrons and they dissolve in water.

Explanation:

Electrolytes are the biology term for ions. They are the same things.

All ions have a "not normal" number of electrons, which gives them a charge. (The number of electrons does not equal the number of protons in the element.)

If the ion gained electrons, it will have a negative charge. if the ion lost electrons, it will have a positive charge.

Generally, elements lose/gain electrons to match the electron configuration of the noble gases, because they have the "perfect" number of electrons. You can use this to find the common charges of ions.
For example, the charge of the sodium ion is +1 (`Na^(+1)`), because when it loses one electron it has the same number of electrons as neon.

All ions dissolve in water.